Used in peptide synthesis as a protected amino acid derivative, enabling selective coupling and preventing side reactions at the guanidine and amine groups. The Boc group protects the alpha-amino function, while the tosyl (Tos) group shields the guanidine moiety of arginine. The N-methylation helps modulate peptide conformation and improve metabolic stability. Commonly applied in the preparation of bioactive peptides, enzyme inhibitors, and pharmaceutical research where precise structural control is required. Its protected form allows stepwise assembly in solid-phase or solution-phase peptide synthesis, ensuring high purity and yield in the final product.